Lee Lip Hong, 39, was sentenced to nine weeks after pleading guilty to having sex with the girl who was 17 at the time.

"He is not appealing and he commences his sentence today," his lawyer Melanie Ho told AFP.

Singapore in 2008 enacted a law making it a crime to pay for sex with a girl under 18 years of age. The offence is punishable by up to seven years in jail.

Before his sentencing, Lee had argued in mitigation that he had no reason to suspect the sex worker was underage, as an online advertisement he had seen prior to hiring the girl listed her age as 18, local daily the Straits Times reported on its website.

He then met the girl in a motel where he had sex with her, paying her Sg$500 ($400) for her services, including a Sg$50 tip.

The other men charged with engaging the girl's services include high-profile business professionals as well as senior police and military officials, with the scandal shaking Singapore's political and economic elite.

The men were nabbed late last year in the biggest police sting operation since laws against underage prostitution were toughened in 2008.